Single joint miter clamp



April 8, 1958 D. H. BRIDGES 2,329,688

SINQLE JOINT MITER CLAMP Filed April 22, 1955 Ila.

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U i ed States P ten SINGLE JOINT MITERCLAMP Don H. Bridges, San Marcos, Tex.

Application April 22, 1955, Serial No. 503,174 1 Claim. (Cl. 144-293) This invention relates to new and useful improvements and structural refinements in cabinet makers tools, and particularly concerns itself with a corner or miter clamp for holding together two pieces of work in an angular relation while the same are being nailed, screwed, glued, or otherwise secured together.

The principal object of the invention is to provide a clamp of this type whereby the work may be firmly and accurately held in its proper position without shifting, spreading or other displacement under the clamp pressure, as commonly occurs when conventional clamps are employed.

Some of the advantages of the invention reside in its simplicity of construction, convenient use, durability and adaptability to economical manufacture.

With the foregoing more important object and features in view, and such other objects and features as may become apparent as this specification proceeds, the invention resides in the details of construction and arrangement of parts substantially as shown in the accompanying drawing, wherein like characters of reference are employed to designate like parts, and wherein:

Figure 1 is a top plan view of the invention;

Figure 2 is a side elevational view thereof;

Figure 3 is a sectional detail, taken substantially in the plane of the line 33 in Figure l; and

Figure 4 is a sectional view, taken substantially in the plane of the line 4-4 in Figure 1.

Referring now to the accompanying drawing in detail, the corner clamp or miter clamp is designated generally by the reference numeral and embodies in its construction an elongated plate-shaped base 11 having a substantially rectangular end portion 11:: and a tapered end portion 11b.

A V-shaped stationary jaw 12 is provided on the base portion 11a, this jaw having an outer face 13 adapted to engage the inside corner of the work 14, 15, as will be hereinafter more fully explained. The jaw face 13 has an apex as shown at 16.

A complemental V-shaped movable jaw 17 is slidably positioned on the base 11 for movement toward and away from the stationary jaw 12, the jaw 17 having an inner face 18 adapted to engage the outside corner of the work 14, 15. The apex of the jaw face 18 is shown at 19.

Means are provided for sliding the jaw 17 toward and away from the jaw 12, these means comprising a screw threaded shaft 20 which is rotatably extended through a screw threaded bore 21 in a bearing block 22 provided at the tapered end of the base portion 11b. The bore 21 is axially aligned with the apices 16, 19 of the respective jaws 12, 17, and the outer end of the shaft 20 is equipped with a suitable handle 23 for rotating the same.

The inner end of the shaft 20 is rotatably connected to the jaw 17, this being achieved by forming the jaw 17 with a centrally disposed socket 24 to rotatably receive the shaft 20. The portion of the shaft in this socket is provided with an annular groove 25 to accommodate a keeper pin 26 provided in the jaw 17, whereby the shaft Patented Apr. 8, 1958 is prevented from sliding out of the socket. The jaw 17 is preferably somewhat higher than the jaw 12 and, as is best shown in Figure 4, the jaw 17 is provided adjacent and at the opposite sides of its apex 19 with elongated recesses or passages,'the purpose of which will be herein-.- after explained. These passages are illustrated at 27.

When the clamp is placed in use, such as for example, in holding two pieces of work 14, 15 at right angles to form a corner, the work pieces are placed in mitered abutment with each other against the face 13 of the stationary jaw 12 and the shaft 20 is rotated so as to bring the face 18 of the movable jaw 17 in pressing engagement with the work pieces. It is to be particularly noted that inasmuch as the stationary jaw 12 engages the inside corner of the work while the movable jaw 17 exerts pressure against the outside corner, the two pieces of work are drawn into firm abutment as the clamp pressure is applied. This arrangement positively safeguards against any possibility of the work pieces shifting or spreading, as often occurs when conventional clamps are being used with a stationary jaw at the outside corner and a movable jaw at the inside corner of the work. By a similar token, since the movable jaw 17 and its operating mechanism 20, 22, 23 are disposed at the outside of the work, the relatively small dimensions of the stationary jaw 12 and its supporting base portion 11a facilitate use of the clamp on relatively small work, particularly where two, three or four clamps are required to be simultaneously used at as many corners.

The provision of the aforementioned recesses or passages 27 in the movable jaw 17 permits nails, screws or other similar fasteners to be driven into the miter joint of the work pieces 14, 15, particularly in small picture frames, and the like, where the work pieces do not project above the jaws.

As already stated, the axis of the bore 21 and, consequently, of the shaft 20 is aligned with the apices 16, 19 of the respective jaws 12, 17 so that under precise working conditions the apices of the jaws perfectly match the inside and outside corners of the work. However, if for any reason there should be some slight deviation in the angularity of the mitered faces of the work pieces, the movable jaw 17 will automatically adjust itself thereto, inasmuch as the shaft 20 is permitted a slight amount of slackness in its engagement with the socket 24 of the jaw 17 and the bore 21 of the block 22 to facilitate a limited amount of lateral displacement of the apex 19 relative to the apex 16. This self-adjusting feature is further facilitated by the fact that the movable jaw 17 merely rests upon the upper surface of the base 11 and is not positively connected thereto by any guides, runners, or the like, which would render lateral adjustment impossible.

While in the foregoing there has been shown and described the preferred embodiment of the invention, various modifications may become apparent to those skilled in the art to which the invention relates. Accordingly, it is not desired to limit the invention to this disclosure, and various modifications may be resorted to, such as may lie within the spirit and scope of the appended claim.

What is claimed as new is:

A miter clamp comprising an elongated base, a V- shaped stationary jaw provided on one end portion of said base and having an outer face adapted to engage an inner corner of the work, a complemental V-shaped movable jaw slidable on said base toward and away from said stationary jaw and having an inner face adapted to engage an outer corner of the work, a stationary block provided on the other end portion of said base and formed with a screw-threaded bore in axial alignment with the apices of the stationary and movable jaws, the apex portion of a screw-threaded shaft extending operatively through the bore of said block and having an end portion thereof rotatable in said socket, the diameter of said bore and of said socket being greater than the diameter of said shaft whereby the shaft engages the bore and the socket with sufiicient slackness to permit limited lateral displace ment of the movable jaw with respect to the stationary jaw in a direction at right angles to the axis of said shaft and also to permit limited upward displacement of the movable jaw to a raised position from said base when the shaft is raised within the slackness thereof in the bore of said block, the end portion of the shaft in said socket being provided with an annular groove, and a keeper pin provided in the apex portion of the movable jaw and pro- 4 jecting into said groove of said shaft whereby the movable jaw is permitted a limited turning movement about the axis of the shaft when the shaft is raised within the slackness thereof in the bore of said block and the movable jaw is in said raised position from said base.

References Cited in the file of this patent UNITED STATES PATENTS 544,072 Schuler Aug. 6, 1895 1,416,874 Reeves May 23, 1922 FOREIGN PATENTS 58,550 Germany Sept. 1, 1891 513,060 Germany Nov. 21, 1930 

